Method To Produce Polymer Matrix Composites

ABSTRACT

This patent describes a new, simple, and low-cost method to produce aromatic thermosetting copolyester (ATSP) based polymer matrix composites. For this method, the ATSP based composites are directly produced from the blended mixtures of the ATSP oligomer powders with the composite fillers through a high temperature and high pressure curing process. In addition, the fully cured ATSP composite laminates can be bonded together to form thicker multi-material composites. The characterization showed that these ATSP based composites are fully condensed, they have excellent tribological performance (low friction and low wear rate), and they have excellent thermal stability, indicating utility in high performance bearing applications, structural materials, and as an ablative composite material.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to provisional application Ser.No. 62/627,337 filed Feb. 7, 2018 entitled Ablative Composites Based onAromatic Thermosetting Copolyester, 62/659,844 filed Apr. 19, 2018entitled Reversible Adhesion and Interchain TransesterificationComposite Welding Mechanism, and 62/786,269 filed Dec. 28, 2018 entitledAdhesive and Processing Methods Utilizing Exchangeable Chemical Bonds,all of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Typically, aromatic thermosetting copolyester resins are produced by atwo-part oligomerization process wherein branched aromatic crosslinkablecopolyester oligomers are synthesized in a melt with average molecularweights between 1000 and 2000 g/mol with monomer feed ratios selectedsuch that the oligomers preferentially are capped with either carboxylicacid or acetoxy functional groups. These are synthesized with an initialfeed of TMA (trimesic acid), (4-acetoxybenzoic acid) ABA, IPA(isophthalic acid), and BPDA (biphenol diacetate). As an example, anoligomer structure designated “CB” (carboxylic acid-capped) oligomerscan be synthesized by melt-condensation of TMA, ABA, IPA and BPDA (molarratio 1:3:2:2, respectively). “AB” (acetoxy-capped) oligomers can besynthesized similarly with a molar ratio 1:3:0:3. These oligomers aretypically brittle, glassy solids at room temperature which can havetheir particle size reduced to micron-scale powder by simple grindingwith a laboratory blender. Following this, the oligomer powders can beloaded into a vibratory sieve with controlled mesh size, which aftervibratory sieving, powders with constrained maximum diameters, forexample less than 90 μm, can be achieved.

Prior methods to produce discontinuous ATSP-based composites haveemployed micron-scale fillers such as graphite powder,polytetraflurorethylene (PTFE) powder, milled carbon fiber, etc. Whenthe carboxylic acid and acetoxy-capped oligomer powder mixture is heatedabove 260° C., acetic acid is released and the ester backbone isformed—advancing the molecular weight. During this process, what haspreviously been seen is that the neat resins will outgas and producefoam structures with significant porosity. To avoid this porosity, curedATSP powders were produced by crosslinking the oligomers, such as CB andAB. CB and AB oligomer powders were mixed at a 1:1 weight ratio andcured via an imposed thermal cycle of 200° C. for 1 h, 270° C. for 2 hfollowed by 330° C. for 3 h wider vacuum. This produces a foam materialwith a typical density of 0.36-0.53 g/cm³. ATSP foamed structures werethen ground to produce powders which pass through a 90 μm mesh sieve ina manner similar to above. However, substantially more grinding time wasnecessary due to the high mechanical properties of the ATSP resin andthe reduction of the particle size becomes a significant rate-limitingstep. Following this, fillers such as milled carbon fiber, PTFE powder,graphite, etc. can be mixed with cured ATSP powder. The mixture then isloaded in a mold and the loaded mold is compressed with 13.8 MPa (2000psi) normal pressure in a vacuumed hot press machine with heatingelements installed in the top and the bottom press plates. Thetemperature increased to 340° C. and held for 2 h for hot sintering ofthe mixture in to bulk ATSP based composites.

Prior method to produce ATSP-based continuous fiber composites usedreinforcements such as carbon fiber or glass fiber fabrics. Blends ofcarboxylic acid and acetoxy-capped oligomer powders, with weight ratioof 1:1.18 were loaded into a container with polar aprotic solvents suchas N-methylpyrrolidone added to the oligomer mixture at a ratio of 0.5gr per mL of solvent. This mixture was blended well with a blade blenderwhile heating the container to 80° C. and held for 4 hours to ensuredissolution of all the solid powder. The warm solution is thenimpregnated into the fabric preforms via processes such as hand layup orvacuum assisted resin transfer molding (VARTM). The temperature is thenramped to 220° C. and held for one hour, then the temperature is rampedto 270° C. and held for one hour, and followed by 340° C. and kept for 2hour. For pressure, the pressure is increased to 0.1 MPa (15 psi) after30 min hold at 220° C., following this the pressure is increased to 6.9MPa (1000 psi) after 1 hour hold at 340° C. and held till the samplecools down. After this heat and pressure cycle, fully condensed ATSPbased continuous fiber composite is formed. The using of solvent in thisprocess is not preferred.

SUMMARY OF THE INVENTION

This patent describes a new, simple, and low-cost method to producecontinuous and discontinuous polymer matrix composite from a pre-polymersystem that generates a volatile by-product as a consequence of its curereaction. For example, the crosslinkable aromatic polyester oligomersevolve acetic acid as their cure by-product, forming an ester bond andthereby advancing molecular weight. The enabling feature that allowsthis is an abundance of exchangeable bonds within the resin. Attemperatures above the glass transition temperature, polymer resins thatfeature exchangeable bonds (that are active in a temperature regime wellbefore the resin begins to thermally degrade) have an additionalmechanism of stress relaxation. Porosity evolved from the generation ofa volatile by-product can be collapsed to negligible values anddensities that approach theoretical values can thereby be achieved.Examples of exchange reactions that enable this process includetransesterification, transimidization, transamidization, urea exchanbe,hydrogen bonding exchange, and sulfone exchange. In this patent, wedemonstrate this principle using aromatic thermosetting copolyester(ATSP) based composites. For this method, we eliminate the need toeither pre-cure any of the ATSP powders or need to use solvent; instead,the ATSP-based composites are directly produced from the mixture of theATSP oligomer powders with the composite fillers thereby eliminatingrate-limiting steps. In the curing process, the acetic acid off-gassingescape from the system between empty spaces and microscopic flow-pathsintroduced by the fillers, with high pressure at high temperature, thecured mixture can be fully condensed using the additional stressrelaxation mechanism as described above. The produced ATSP basedcomposites have excellent thermal stability and tribological performanceand the laminates of the composites can be bonded together ex-situ toform thicker multi-material composites.

BRIEF DESCRIPTION OF THE FIGURES

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fees.

A fuller understanding of the foregoing may be had by reference to theaccompanying drawings, wherein:

FIG. 1 is a picture of a produced fully dense composite of ATSP with 28wt. % chopped IM-9 carbon fiber;

FIG. 2 illustrates TGA curves showing remaining weight percentage vs.temperature for different composites;

FIG. 3 is a graph illustrating a curve of curing parameters fortemperature and pressure;

FIG. 4 is an illustration of the production process for ATSP composites,mixture of ATSP oligomers (CB and AB) with milled carbon fiber in a2″×2″ mold on the left, and final consolidate 2″×2″ ATSP composites;

FIG. 5 shows SEM image of consolidate ATSP+30% milled carbon fibercomposite with different magnifications;

FIG. 6 is an illustration of a Pin-on-disk tribological experimentalconfiguration;

FIG. 7 are Tribological experimental results, friction results on theleft and wear rate result on the right;

FIG. 8 is an illustration of a Cylindrical mold for producing ATSP-basedtilting pad bearings;

FIG. 9 is a photo of a Finished ATSP-based tilting pad bearing;

FIG. 10 shows examples of ATSP based continuous fiber composites, fromleft to the right: ATSP-carbon fiber vail, ATSP-glass fiber weave,ATSP-glass fiber weave, and ATSP-carbon fiber weave;

FIG. 11 shows different methods to spread ATSP oligomer powders on thecontinuous fiber weaves/sheets, dry powder bath (top left), dry powderspray (top right) and wet slurry method (bottom);

FIG. 12 shows sample of ATSP-glass fiber composite, uncured stack ofoligomer powder and glass fiber mixed sheet (left), cured ATSP-glassfiber composite (right);

FIG. 13 is a graph illustrating a curve of curing parameters fortemperature and pressure; and

FIG. 14 shows the production of multilayer ATSP based composite, ATSP/MFdenotes CBAB:milled carbon fiber (70:30), ATSP coating denotes CBABcoating on aluminum sheet, Neat ATSP is neat CBAB, and ATSP/CF denotesCBAB:chopped carbon fiber (70:30).

DESCRIPTION OF THE INVENTION

Referring now to the figures, a process is described to produce fullydense materials of ATSP in spite of the off-gassing of the acetic acid.Once the oligomer powder mixture is blended with the right concentrationof other fillers, such as milled carbon fiber, chopped carbon fiber,continuous fibers, and powders (ceramic powder, graphite, PTFE, etc.),the acetic acid produced at a high curing temperature can leak outthrough the free space among the fillers. Once the cure finishes, withcompressive pressure at high temperature, the cured mixture/blend canconsolidate and approach theoretical density. These composites can beused for variety of applications, such as for ablative material, bearingmaterial, structure material, etc. Embodiments of the present inventionprovide a method for fabricating ATSP based composites and moregenerally a method for producing composites in cases where a by-productis evolved by the cure reaction but the resin features exchangeablebonds.

In an embodiment of the present invention, ATSP-chopped carbon fibercomposite is produced directly from ATSP oligomers and chopped carbonfiber mixture. In accordance with such embodiments, ATSP oligomers andchopped carbon fiber are added together and then blended well in ablender. Then, the blended mixture is loaded in a mold, goes through ahigh temperature cure and compression cycle and forms the finalATSP-chopped carbon fiber composite. Different length and differentmaterial of chopped fibers are applicable for the same fabricationprocess.

In another embodiment of the present invention, ATSP-milled carbon fiber(and other small size fillers) composites are produced directly fromATSP oligomers and small size fillers mixture. In accordance with suchembodiments, ATSP oligomers and small size fillers are added togetherwith desired weight ration and then blended well in a blender. Then, theblended mixtures are loaded in a mold, and go through a high temperaturecure and compression cycle and form the final ATSP-based composites.Various filler materials, combination of different fillers and differentweight ratios are applicable for the same fabrication process with thesignificant requirement being that they do not melt or significantlythermally degrade as a consequence of the process cycle.

In another embodiment of the present invention, ATSP/milled carbon fibercomposite is directly produced from ATSP oligomers and milled carbonfiber mixture; and the composite is attached on a metal surface at thesame time. In accordance with such embodiments, ATSP oligomers andmilled carbon fiber filler are added together with desired weight rationand then blended well in a blender. The mixture is loaded in a mold suchthat one side of the mold is mounted with the metal backing plate coatedwith ATS. Then, the blended mixture goes through a high temperature cureand compression cycle and form the final ATSP-milled carbon fibercomposite attached on the coated metal. Various filler materials,combination of different fillers and different weight ratios areapplicable for the same fabrication process. And the bonding betweenATSP composites and metal can be also supplied by mechanicalinterlocking, such as dovetail grooves on metal substrate surface andsintered porous metal (e.g. bronze) powder on metal substrate surface.

In another embodiment of the present invention, ATSP-based multilayercomposite was produced by bonding several plates of cured ATSPcomposites or ATSP-coated aluminum. Cured ATSP-milled carbon fiber andATSP-chopped carbon fiber composite are directly produced from ATSPoligomers and milled/chopped carbon fiber mixtures. In accordance withsuch embodiments, ATSP oligomers and milled/chopped carbon fiber fillerare added together with desired weight ration and then blended well in ablender. Load the mixtures in a mold that go through a high temperaturecure and compression cycle and form the final ATSP-milled/chopped carbonfiber composites. Stack the cured ATSP composites and ATSP coatedaluminum sheets in desired order and load the stack in hot press machinefor a hot sintering process; and a multilayer composites can be formed.Various filler materials, combination of different fillers and differentweight ratios are applicable for the same fabrication process. And thebonding between ATSP composites and metal can be also supplied bymechanical interlocking, such as dovetail grooves on metal substratesurface and sintered porous metal (e.g. bronze) powder on metalsubstrate surface.

In another embodiment of the present invention, ATSP based continuousfiber composites are produced directly from ATSP oligomers andcontinuous fiber weave mixture. In accordance with such embodiments,ATSP oligomers are deposited on the continuous fiber weave with threedifferent ways: dry powder bath, dry powder spray and wet slurry method.Then, the blended mixtures are loaded in a hot press machine, and gothrough a high temperature cure and compression cycle and form the finalATSP-based continuous fiber composites. Various continuous fibermaterials, with different formats (weave sheet, unidirectional fabric,tow, etc.), combination of different fillers and different weight ratiosare applicable for the same fabrication process.

Example 1: ATSP-Chopped Carbon Fiber Composite

This example demonstrates the production of discontinuous ATSPcomposites filled with chopped carbon fiber (other chopped fibers suchas glass fibers work with the same principle). First, mix the twooligomers (CB and AB) with desired weight percentage of chopped carbonfiber. Then the blended components are loaded into a mold and placed ina hot press. The hot press is ramped to 270° C. and held for one hourwith no pressure applied to the mold. After one hour, the temperature isramped to 360° C. At 360° C., the pressure is increased to 27.6 MPa(4000 psi) and the sample is held for 2 hours and then allowed to cool.An example of a fully dense discontinuous composites produced by thismethod (as seen in FIG. 1) is one where the filler was ¼″ chopped IM-9carbon fiber (by Hexcel) was 28 wt. % of the composite. Initial thermalexperiments on this are described below.

Thermal degradation of the composites was performed by a TGA (TA-2950)from room temperature to 800° C. with heating rate of 10° C./min undernitrogen.

Table 1 and FIG. 2 show the TGA results, it is clear that ATSP-CBAB andits carbon composite have much better thermal stability, both the neatATSP and its composite have 186° C. to 210° C. higher temperaturecompared with Phenolic+50 wt. % glass fiber composite with respect totheir degree of thermal degradation at 5%, 10% and 25% of weight loss.Compared with neat ATSP, the neat Phenolic resol in also showed worsethermal stability even with a faster beating rate of 20° C./min. As forMXBE-350, its thermal stability is also worse than neat ATSP; forMXB-360, compared with neat ATSP, it has a lower temperature at 5 wt. %loss but higher temperature at 10 wt. % loss, while the highertemperature is strongly determined by its high percentage (73.5%) offillers. Thus, if we design ATSP composites with different fillers orcomplex structures, ATSP will have promising and favorable thermalperformance.

TABLE 1 Materials used in the proof-of-concept TGA and results atseveral mass loss points as well as residual mass after 800° C. (charyield) Filler Density T_5 wt % T_10 wt % T_25 wt % Residual massMaterials (%) (g/cm³) loss loss loss at 800° C. 1. ATSP-CBAB 0 1.3 478°C. 496° C. 518° C. 45.3% 2. ATSP-CBAB + 28 1.42 476° C. 498° C. 532° C.57.6% chopped carbon fiber 3. G10 Phenolic 50 1.94 282° C. 310° C. 322°C. 61.9% glass fiber composite Phenolic resol 0 1.3 260° C. 310° C. 480°C.  52% MXB-360 73.5 1.8 383° C. 527° C. N/A  85% MXBE-350 56.5 1.72322° C. 383° C. 485° C.  68%

Example 2: ATSP-with Different Fillers

As for Tribological applications, polymers in pure form as unfilledpolymers may have high COF, high wear rate and poor mechanicalproperties, so they typically do not satisfy the tribologicalapplication needs. Thus, it is of great interest in producing compositesor blended polymers by adding different fillers and reinforcements inthe polymers, improving significantly their mechanical, thermal ortribological properties. In this example, we produced ATSP bearing gradecomposites by mixing ATSP oligomers with different fillers such asmilled carbon fiber (Zoltek PX35MF0150), graphite powder, PTFE powder,carbon black, carbon nanotubes, and graphene nanoplatelets withdifferent weight percentages. Examples of mixing ratio between ATSP andfillers that have been tried is listed in

Table 2.

TABLE 2 Examples of mixing ratio between ATSP and fillers Composition ofthe mixture No. (CBAB is mixed of CB and AB oligomers with 50:50 weightratio) 1 CBAB:milled carbon fiber (70:30) 2 CBAB:milled carbonfiber:Teflon ® PTFE 7A X (60:30:10) 3 CBAB:Teflon ® PTFE 7A X (70:30) 4CBAB:carbon nanotubes (90:10) 5 CBAB:graphite (60:40) 6CBAB:graphite:Teflon ® PTFE 7A X (50:40:10) 7 CBAB:graphene (90:10) 8CBAB:graphite:Teflon ® PTFE 7A X:milled carbon fiber (55:15:15:15)

The parameter curve for curing of the mixture of ATSP oligomers and thefillers is shown in FIG. 3: the mixture composition was loaded into themold (as in FIG. 4 on the left) followed by the mold anvil. Loaded moldwas placed into a vacuum-enclosed hot press. A temperature cycleconsisting of a 5° C./min ramp to 330° C. followed by a 150 min holdfollowed by a 1° C./min ramp to 360° C. with a 2 hours hold and thencool down naturally. After 1 hour hold at 360° C., applied the pressureof 6.9 MPa (1000 psi) for the mold and hold till the sample cooled down.ATSP composites were removed from the mold and can be seen in FIG. 4 onthe right. These 2″×2″ plates were produced with thickness of about0.4″. As shown in FIG. 5 of the SEM analysis of ATSP+30% milled carbonfiber composite, the sample was fully condensed and the milled carbonfiber filler are uniformly distributed in the composite.

The composites showed excellent machinability and they were made into ¼″cylindrical pins for tribological performance evaluation by apin-on-disk experimental configuration, as shown in FIG. 6. Thetribological experiments were performed by a tribometer allowing to doexperiment with different conditions such as load, speed andtemperature. The counterpart of the composite pin was a 2″ diameter diskmade from 416 stainless steel, with root mean square roughness of 0.1μm. The experimental conditions were: dry sliding, temperature of 25°C., sliding speed of 0.5 m/s and contact pressure of 4 MPa. Both normaland friction forces were recorded and used for calculation ofcoefficient of friction (COF), which is the ratio of friction force andnormal force. The wear rate, with unit of mm³/Nm, was calculated bydividing wear volume by the product of normal force and the slidingdistance. The friction and wear rate results are shown in FIG. 7. Forcomparison, two commercial bearing grade polymer composites wereselected: DuPont™ Vespel® SP-21 and Ketron®@ HPV PEEK. Among the 6different composites that were tested, ATSP+30% PTFE showed lowest COFof 0.27±0.01, corresponding with a very low wear rate of 3.2×10-7mm³/Nm; and ATSP+40% Graphite+10% PTFE had lowest wear rate of 2.7×10⁻⁷mm³/Nm, corresponding with COF of 0.29±0.01. Both these two ATSPcomposites had better tribological performance compared with the twocommercial composites, where Vespel SP21 had COF 0.50±0.06 with wearrate of 49×10-7 mm/Nm and HPV PEEK had COF 0.38±0.06 with wear rate of107×10-7 mm³/Nm with the same experimental conditions. Thesetribological results show the utility of ATSP composites as highperformance bearing materials.

Example 3: ATSP Based—Metal Composite

Tilting pad bearings (for use in e.g. electrical submersible pumps) werefabricated using a filled composition of ATSP. A 304 stainless steelbase was roughened by grit blast and subsequently cleaned viaultrasonication in isopropanol and then dried at 70° C. A mixed layer ofCB and AB ground oligomeric powders (50:50 mass ratio, mesh size <90 um)were deposited via electrostatic powder deposition. The depositedcoating was melted and cured via convection oven at 270° C.

The coated 304 base was inserted into a cylindrical mold as shown inFIG. 8. A blend of CB:AB oligomers (at 50:50 mass ratio) was mixed withmilled carbon fiber (Zoltek PX35MF0150) and PTFE at mass proportions of70:25:5 and thoroughly blended in a laboratory blender. Blendedcomposition was loaded into the mold followed by the mold anvil. Loadedmold was inserted into a vacuum-enclosed hot press. A temperature cycleconsisting of a 2° C./min ramp to 270° C. followed by a 30 minute holdfollowed by a 2° C./min ramp to 340° C. with a one hour hold followed bya 2° C./min ramp to 370° C. with a hold for 2 hours. At the start of the370° C. hold, the applied pressure on the mold is increased to 4000 psi.Sample is allowed to cool naturally. Specimen was removed from the moldand then machined into correct dimensions, as seen in FIG. 9. Thebonding between ATSP composite and the 304 ss substrate was created bythe electrostatic powder coating, in addition to this coating method,the bonding could also be supplied by mechanical interlocking, such asdovetail grooves on metal substrate surface and sintered porous metal(eg. bronze) powder on metal substrate surface. The ATSP composite canthereby achieve mechanical interlocking and occupy the free space on themetal substrate and then ensure the ATSP composite on the metalsubstrate is well-attached.

Example 4: ATSP Based Synthetic Multilayer Composites

To produce the ATSP based synthetic multilayer (5 layers) composite asshown in FIG. 14 on the right, 3 different fully condensed ATSPcomposites, namely CBAB:milled carbon fiber (70:30), neat CBAB, andCBAB:chopped carbon fiber (70:30), and two aluminum plates depositedwith CBAB coating need to be produced, as in FIG. 14 on the left.ATSP/milled carbon fiber composite plate was produced with same methodas in Example 2 and ATSP/chopped carbon fiber composite plate wasproduced with same method as in Example 1.

Neat CBAB plate was produced as below: cured CBAB powders were producedby first crosslinking the CB and AB oligomers. CB and AB oligomers weremixed at a 1:1 weight ratio were mixed and cured via an imposed thermalcycle of 200° C. for 1 h, 270° C. for 2 h followed by 330° C. for 3 hunder vacuum. This produces a foam material with a typical density of0.36-0.53 g/cm³. ATSP foamed structures were then ground to producepowders which pass through a <90 μm mesh. The cured ATSP powder was thenloaded into the mold was compressed with 6.7 MPa (1000 psi) normalpressure in a vacuumed hot press machine with heating elements installedin the top and the bottom press plates. The temperature increased to340° C. and held for 2 h for hot sintering of ATSP powders in to bulkplate.

To produce the CBAB coating on aluminum, the aluminum substrate wasroughened by grit blast and subsequently cleaned via ultrasonication inisopropanol and then dried at 70° C. A mixed layer of CB and AB groundoligomeric powders (50:50 mass ratio, mesh size <90 um) were depositedvia electrostatic powder deposition. The deposited coating was meltedand cured via convection oven at 270° C.

With the 5 plates as in FIG. 14 on the left, they were stacked togetherin the mold in order: 1) CBAB:milled carbon fiber, 2) ATSP coating, 3)neat CB AB, 4) ATSP coating, and 5) CBAB:chopped carbon fiber, followedby the mold anvil. Loaded mold was inserted into a vacuum-enclosed hotpress. A temperature cycle consisting of a 2° C./imin ramp to 340° C.followed by a 2 hours hold. At the start of the 340° C. hold, theapplied pressure on the mold is increased to 13.8 MPa (2000 psi). Thesample is allowed to cool naturally. Specimen was removed from the moldand then machined into correct dimensions, as seen in FIG. 14 on theright.

Example 5: ATSP-Continuous Glass Fiber (and Carbon Fiber, Etc.)Composites

To produce the ATSP-continuous glass fiber (and carbon fiber, etc.)composites as shown in FIG. 10, the continuous fiber weaves/sheets needto be covered by the ATSP oligomer powders (CB and AB powders for thispatent). In this patent, as shown in FIG. 11, we demonstrate threedifferent methods to spread ATSP oligomer powders on the continuousfiber weaves/sheets, namely, dry powder bath, dry powder spray and wetslurry method. As for the dry powder bath method, place the fiber sheeton the top of the powder in the glass tray, and then press the all thefiber sheet area lightly with a sponge that is fulfilled with oligomerpowder. By this way the fiber sheet will be fully covered by theoligomer powder. Following this, the oligomer saturated fiber sheets arearranged in a stack, as in FIG. 12 (left), and then the stack of sheetsis placed in a hot press machine. As shown in FIG. 13, the curve ofcuring parameters for temperature and pressure. For temperature cycle:the temperature is ramped to 220° C. and held for one hour, then thetemperature is ramped to 270° C. and held for one hour, the temperatureis then ramped to 360° C. and kept for one hour. For pressure cycle, thepressure is increased to 0.1 MPa (15 psi) after 30 min hold at 220° C.,and then the pressure is increased to 6.9 MPa (1000 psi) and held tillthe sample cools down. At 220° C., with low pressure, the oligomers meltand can wet through the fiber bundles; at 330° C. for 1 hour, ATSPoligomers can finish the reaction; at 360° C. for 1 hour, with help ofhigh pressure, the cured ATSP resin in the composite softens and form aconsolidated ATSP based continuous fiber composite with densityapproaching theoretical. After the curing cycle, the finished ATSP-glassfiber composite is shown in FIG. 12 (right).

While particular elements, embodiments, and applications of the presentinvention have been shown and described, it is understood that theinvention is not limited thereto because modifications may be made bythose skilled in the art, particularly in light of the foregoingteaching. It is therefore contemplated by the appended claims to coversuch modifications and incorporate those features which come within thesprint and scope of the invention.

1. A method of producing aromatic thermosetting copolyester (ATSP) basedcomposites, comprising: preparing mixtures of ATSP oligomer powders andfillers; curing the mixture of ATSP oligomer powders and fillers at anelevated temperature, ranged between 270° C. and 400° C. to create acured mixture; consolidating the cured mixture in a high pressure,ranged between 0.1 MPa and 20 MPa; and wherein the ATSP oligomer powdersconsist of pairs of carboxylic acid-capped and acetoxy-capped oligomers,and wherein the fillers consist of discontinuous fillers and continuousfillers; and wherein the discontinuous fillers consist of milled carbonfiber, chopped carbon fiber, chopped glass fiber, milled glass fiber,ceramic powder, graphite, carbon nano tubes, graphene, andpolytetrafluorethylene (PTFE) powder; and wherein the continuous fillersconsist of continuous carbon fiber and continuous glass fiber, in theformats of weave sheet, unidirectional fabric sheet, unidirectional tow.2. The method of claim 1, wherein the step of preparing mixtures of ATSPoligomer powders and fillers are achieved by adding of ATSP oligomerpowders and discontinuous fillers in a predetermined weight ratios andthen blending together in a blender.
 3. The method of claim 1, whereinthe step of preparing mixtures of ATSP oligomer powders and fillers areachieved by depositing of ATSP oligomer powders on continuous fillerswith a solvent free method, and wherein the solvent free method consistsof one of the following: dry powder bath, dry powder spray, and wetslurry.
 4. The method of claim 1, wherein the step of curing the mixtureof ATSP oligomer powders includes a temperature between 270° C. and 400°C., and wherein the ATSP oligomer powders are formed by crosslinking thecarboxylic acid-capped oligomer and the acetoxy-capped oligomer.
 5. Themethod of claim 1, wherein the consolidation of cured mixture isachieved by setting a pressure 0.1 MPa and 20 MPa during a temperaturerange of 270° C. and 400° C.
 6. A method of producing aromaticthermosetting copolyester (ATSP) based composites attached on metalsubstrate, comprising: preparing mixtures of ATSP oligomer powders andfillers; preparing a metal substrate; curing the mixture of ATSPoligomer powders and fillers between a temperature range of 270° C. and400° C. with the metal substrate as a backing plate to create a curedmixture; consolidating the cured mixture in a pressure range between 0.1MPa and 20 MPa; and wherein the ATSP oligomer powders consist of pairsof carboxylic acid-capped and acetoxy-capped oligomers, and whereinfillers consist of discontinuous fillers and continuous fillers, andwherein the discontinuous fillers consist of milled carbon fiber,chopped carbon fiber, chopped glass fiber, milled glass fiber, ceramicpowder, graphite, carbon nano tubes, graphene, andpolytetrafluorethylene (PTFE) powder, and wherein the continuous fillersconsist of continuous carbon fiber and continuous glass fiber, in theformats of weave sheet, unidirectional fabric sheet, unidirectional tow.7. The method of claim 6, wherein the step of preparing mixtures of ATSPoligomer powders and fillers are achieved by adding of ATSP oligomerpowders and discontinuous fillers in a predetermined weight ratio andthen blending together in a blender.
 8. The method of claim 6, whereinthe metal substrate is prepared by a surface treatment, wherein thesurface treatment is achieved with one of the following: particle blastroughening, dovetail shape machining, and particle (bronze) sintering.9. The method of claim 6, wherein the step of curing the mixture of ATSPoligomer powders includes a temperature between 270° C. and 400° C., andwherein the ATSP oligomer powders are formed by crosslinking thecarboxylic acid-capped oligomer and the acetoxy-capped oligomer.
 10. Themethod of claim 6, wherein the step of preparing mixtures of ATSPoligomer powders and fillers are achieved by depositing of ATSP oligomerpowders on continuous fillers with a solvent free method, and whereinthe solvent free method consists of one of the following: dry powderbath, dry powder spray, and wet slurry.
 11. The method of claim 6,wherein the consolidation of cured mixture is achieved by setting apressure between 0.1 MPa and 20 MPa during a temperature range ofbetween 270° C. and 400° C.
 12. A method of producing aromaticthermosetting copolyester (ATSP) based composites attached with eachother to form multilayer composite, comprising: preparing mixtures ofATSP oligomer powders and fillers; preparing metal plates; curing themixture of ATSP oligomer powders and fillers between a 270° C. and 400°C. to create a cured mixture; consolidating the cured mixture in apressure range between 0.1 MPa and 20 MPa; and sintering the curedmixture and metal plates together; and wherein the ATSP oligomer powdersconsist of pairs of carboxylic acid-capped and acetoxy-capped oligomers,and wherein fillers consist of discontinuous fillers and continuousfillers, and wherein the discontinuous fillers consist of milled carbonfiber, chopped carbon fiber, chopped glass fiber, milled glass fiber,ceramic powder, graphite, carbon nanotubes, graphenic platelets, andpolytetrafluorethylene (PTFE) powder, and wherein the continuous fillersconsist of continuous carbon fiber and continuous glass fiber, in theformats of weave sheet, unidirectional fabric sheet, unidirectional tow.13. The method of claim 12, wherein the step of preparing mixtures ofATSP oligomer powders and fillers are achieved by adding of ATSPoligomer powders and discontinuous fillers in a predetermined weightratios and then blending together in a blender.
 14. The method of claim12, wherein the metal plates are prepared by surface treatment, andwherein the surface treatment is achieved with one of the following:particle blast roughening, dovetail shape machining, and particle(bronze) sintering.
 15. The method of claim 12, wherein the step ofcuring the mixture of ATSP oligomer powders includes a temperaturebetween 270° C. and 400° C. and wherein the ATSP oligomer powders areformed by crosslinking the carboxylic acid-capped oligomer and theacetoxy-capped oligomer.
 16. The method of claim 12, wherein the step ofpreparing mixtures of ATSP oligomer powders and fillers are achieved bydepositing of ATSP oligomer powders on continuous fillers with a solventfree method, and wherein the solvent free method consist of one of thefollowing: dry powder bath, dry powder spray, and wet slurry.
 17. Themethod of claim 12, wherein the consolidation of cured mixture isachieved by setting a pressure of between 0.1 MPa and 20 MPa during atemperature range of between 270° C. and 400° C.
 18. The method of claim12, wherein the sintering of the cured plates and metal plates togetheris achieved by setting a pressure 0.1 MPa and 20 MPa during atemperature range of 270° C. and 400° C.
 19. A method of producingcrosslinkable polymer-based composite, comprising: preparing mixtures ofoligomers, and fillers, ranged between 100° C. and 400° C. to create acured mixture, and wherein the oligomers are configured to cure by acondensation mechanism and which possess moieties that are labile at anelevated temperature, consolidating the cured mixture in a highpressure, ranged between 0.1 MPa and 20 MPa; and wherein thecrosslinkable oligomers have matched functional end-caps such that acondensation by-product is released as a consequence of their curereaction; and wherein the fillers consist of discontinuous fillers andcontinuous fillers; and wherein the discontinuous fillers consist ofmilled carbon fiber, chopped carbon fiber, chopped glass fiber, milledglass fiber, ceramic powder, graphite, carbon nano tubes, graphene, andpolytetrafluorethylene (PTFE) powder; and wherein the continuous fillersconsist of continuous carbon fiber and continuous glass fiber, in theformats of weave sheet, unidirectional fabric sheet, unidirectional tow.20. A method of producing crosslinkable polymer-based composite basedcomposites attached on metal substrate, comprising: preparing mixturesof crosslinkable oligomers and fillers; preparing a metal substrate;curing the mixture of crosslinkable oligomers and fillers between atemperature range of 100° C. and 400° C. with the metal substrate as abacking plate to create a cured mixture; consolidating the cured mixturein a pressure range between 0.1 MPa and 20 MPa; and wherein thecrosslinkable oligomers have matched functional end-caps such that acondensation by-product is released as a consequence of their curereaction; and wherein the fillers consist of discontinuous fillers andcontinuous fillers; and wherein the discontinuous fillers consist ofmilled carbon fiber, chopped carbon fiber, chopped glass fiber, milledglass fiber, ceramic powder, graphite, carbon nano tubes, graphene, andpolytetrafluorethylene (PTFE) powder; and wherein the continuous fillersconsist of continuous carbon fiber and continuous glass fiber, in theformats of weave sheet, unidirectional fabric sheet, unidirectional tow.